An annotated timeline displays a list of dates along with a sentence or brief summary detailing the significance of each date. These timelines illustrate the big picture of an era and help readers understand the major events that happened during that time.

Choose a theme. Without a theme, your annotated timeline will seem like a jumbled mess of dates. A theme can be simple and broad, such as "United States: 1900--1910," or narrow and focused, such as "Battles of the French Revolution."

Design a format your timeline. The typical annotated timeline has the date aligned on the left and the annotation directly next to it, usually separated by a colon or dash.

Choose dates and events that are the most vital to understanding your theme. The number of dates you choose depends on your scope, but they must all relate to your theme.

Write your annotation. For each event, include information such as the names of the people involved, the actions that occurred and their significance. Annotations should be relatively brief. A single sentence can suffice. The purpose of an annotated timeline is to condense information into small, manageable chunks.

Display your dates in a consistent manner.